The use of hematoporphyrin derivative (HPD) in combination with red light is currently under investigation as an anti-cancer treatment modality. A major advantage of this therapy is the purported selectivity of tumor versus normal tissue response. Studies have been designed and are currently underway to establish HPD retention in normal versus tumor tissue in a murine model. An ovarian tumor model will be used to determine the pharmacodynamics of HPD, optimization of HPD delivery, laser penetration, dose, and timing of drug and light delivery within the peritoneal cavity.